Actualités – SNLEP

The Université de Lyon proposes in the section “Doctorat”, the setting up of a new system initiated by the Department of Doctoral Studies at the University of Lyon, with the expertise of OPE (Objective for Employment), ” From Doctorate to Employment “.

It is presented in the form of a six-month program led by experts, for the support of doctors tailored to the search for a permanent job outside the academic sector. This course is based on a collective dynamic led by professional trainers, and associated with a personalized accompaniment adapted to their profile.

On Thursday, September 14, at 2:00 pm in room E302 of the CPE building, Swann Marx (GIPSA Lab-LAGEP) will present his thesis work. He will support his thesis on 20 September in Grenoble. His work focuses on the stabilization of EDPs by saturated control.

This is the summary of his presentation.

ABSTRACT :
This thesis provides contributions in stabilization methods for nonlinear dynamical systems. In particular, it focuses on two main subjects: the analysis of infinite-dimensional systems subject to saturated inputs and the design of output feedback laws for either infinite-dimensional or finite-dimensional systems.

The presentation will focus on the first subject.

In the first part, we will introduce a more general class of saturations than the one known for finite-dimensional systems. When bounding a linear stabilizing feedback law with such nonlinearity, a well-posedness result together with an attractivity result will be stated for systems whose open-loop is defined by operators generating strongly continuous semigroup of contractions. The attractivity result will be proved by using the LaSalle’s Invariance Principle together with some compactness properties.

In the second part, a particular nonlinear partial differential equation is studied, namely the Korteweg-de Vries equation, that models long waves in water of relatively shallow depth. A control actuating on a small part of the channel will be considered. This control will be modified with two different types of saturations. The attractivity result will be proved by using Lyapunov argument and a contradiction argument. Finally, the results will be illustrated with some numerical simulations.

Title : Why we need Riemannian Geometry for the Control of the Wave Equation with Variable Coefficient,
Pengfei YAO, Academy of Mathematics and Systems Science, Academia Sinica.

Abstract: I will present a brief comparison between several methods which have been used in the literature to show why Riemannian geometry is necessary for control of the wave equation with variable coefficients. The classical multipliers are generalized to a version of the Riemannian geometry setting with help of the Bochner technique to find out verifiable geometric assumptions for control of the wave equation with variable coefficients in space. Thus controllability/stabilization of the wave equation with variable coefficients comes down to an escape vector field for the Riemannian metric, given by the variable coefficients.

Abstract: In the last two decades, there is a new emerging control technology called active disturbance rejection control (ADRC) proposed by Jingqing Han of the Chinese Academy of Sciences, which has been widely used in engineering control in many countries. Progress from a theoretical perspective was made only in last few years. In this talk, I will briefly introduce ADRC and focus on some recent results on extended state observers for nonlinear systems, a key part of ADRC. Numerical results are also presented to compare with other control methods.

These scientific days are an unmissible annual meeting for the laboratory. They are an excellent opportunity for the PhD students to present their angoing research (oral presentations and poster sessions) to the laboratory staff and partners. They will take place on June 22nd and 23rd, 2017 at Petit-Amphi of CPE Lyon. Event not to be missed !

Fulvio Forni, a Cambridge University researcher, begins Monday his “guest month” at the LAGEP.

You can find information on its research topic here:

Https://sites.google.com/site/fulvioforni/

He will give a seminar on Tuesday 04/04/2017, 2:00 pm in the Bordet room.
Title
Differential analysis of nonlinear systems: positivity, monotonicity and interconnections.

Abstract
Differential analysis aims at inferring global properties of nonlinear behaviours from the local analysis of the linearised dynamics. The novel notion of differential positivity extends linear positivity to the nonlinear setting: a nonlinear system is differentially positive if its linearization along trajectories leaves a cone (field) invariant. Notably, monotone systems are differentially positive. Differential positivity extends monotonicity to manifolds, replacing order relations with local orders. The property strongly restricts the asymptotic nonlinear behavior, through suitable extensions of Perron-Frobenius theory and of results on contraction of the Hilbert metric. Motivated by the importance of positivity in linear systems theory, we discuss the relevance of the property for applications and how much the property restricts the behavior of open nonlinear systems.

During the Control @ Lyon days, Yue-Jun Peng, Professor at Blaise Pascal University, will give a seminar on Thursday (30/03/2017) at 2:00 pm at LAGEP in the Bordet room.

Title. Strong>
Introduction to quasi-linear hyperbolic systems,

Summary. Strong>
In this paper, we first introduce The quasi-linear hyperbolic system. Results On the local existence of regular solutions to the Cauchy problem.
By a simple example, we show a fundamental property Of the system concerning singularity formation of solutions In finite time. We then introduce the notion of weak solutions And entropy. Finally, we consider the problem at Conditions of Dirichlet. This one is very useful to study the problem of exact controllability of the system.